Active Sync Authentication Error

Hello All,

I hope someone can help me. I am pulling my hair from past three days.

We have three HTC Desire with Active Sync configured to our SBS 2003
Exchange. Till Last week it was working perfectly until one phone had problem
syncing Calendar items. I looked at the log and found the following 4 errors
for Calendaring Sync.

Event ID: 3005
Description: Unexpected Exchange mailbox Server error: Server:
[xx.xxx.local] User: [] HTTP status code: [500]. Verify that the
Exchange mailbox Server is working correctly.

Event ID: 8199
Description: Calendaring agent failed in message save notification with
error 0x80040219 on :
/Calendar/{814EBC9B-2AF3-4F15-9707-4FCF7AAB84F6}.EML.

Event ID: 8206
Description: Calendaring agent failed with error code 0x80040219 while
saving appointment.

Event ID: 8260
Description: An attempt was made to save an appointment with the subject
"Dad's Birthday" to mailbox . The duration of the appointment was
too large, so it was not saved.

I looked on Google and in one forum it suggested to install Hotfix
(KB943721). After installing or whatever changes I made on Exchange or IIS
everything stopped working.

Now none of the mobile can sync with email using ActiveSync. In total 5
mobile which was working last week stopped working.

On HTC I get – Authentication Failed. Please verify Username and/or password.

From Windows Mobile - activesync not an exchange server or incompatible
software and error number 0x80072f17.

I uninstalled hotfix (KB943721) and still the problem persist. I don’t know
/ remember or not sure what other changes was made when fixing the calendar
issue.

I tried all the suggestion shown on the internet, checked all the security
permission on the Virtual Folders on IIS. Still the Activesync is not
connecting.

When I see the IIS log, there is entry for the phone.
2010-08-12 14:55:00 W3SVC1 192.168.28.7 OPTIONS /Microsoft-Server-ActiveSync
User=mstott&DeviceId=HTCAnd6a422c49&DeviceType=htc bravo 80 - 193.35.132.10
Android-EAS/0.1 200 0 0

Can anyone please help to solve this issue.

Many thanks.....